Strong battery, cooler device

iOS 26.3 Beta 1 brings impressive temperature control of only 33 degrees Celsius and significantly improved battery life compared to version 26.2.

Just when users haven’t had time to explore all the features on the official iOS 26.2, Apple has continued to release the iOS 26.3 Beta 1 test version for developers with a fairly large capacity, about 8.52 GB on iPhone 17 Pro Max. The Build number this time is 23D5089E.

Although it is the first Beta version, initial experiences in performance and battery life are showing extremely positive signals, even superior to the recently released official version.

Upgrade your device now to experience new, smoother features:

Impressive temperature control capabilities

One of the most valuable improvements in iOS 26.3 Beta 1 is the ability to manage heat (Thermals). In actual tests using a thermal camera when the machine is running heavy tasks, the temperature measured at the hottest point is only about 33 degrees Celsius.

This is a clear improvement compared to iOS 26.2 (which usually fluctuates around 36.7 degrees Celsius under the same conditions).

The fact that the device operates cooler not only makes it comfortable to hold, but also ensures stable performance over a long period of time, avoiding screen brightness reduction or lag due to overheating when playing games or using outdoors.

Smooth performance and interface bug fixes

Regarding daily use experience, iOS 26.3 Beta 1 is considered “super smooth”, even smoother than version 26.2.

Swiping, opening applications or accessing the App Library all take place instantly without any delay. Annoying graphics errors such as ghosting in Control Center or frame stuttering have been completely fixed.

Regarding technical scores, Benchmark tests show stability. The single-core score is about 3,828 and the multi-core score is 9,769.

Although the multi-core score may be slightly lower than some tests on iOS 26.2, this difference is within the allowable error margin. In return, the smoothness in transition effects (animation) is what users can feel most clearly right after the update.

Battery life has jumped by leaps and bounds

The battery data on iOS 26.3 Beta 1 is truly surprising. On the test device (iPhone 17 Pro Max with 100% battery capacity, 32 charging cycles), on the first day of use, the device only consumed 44% of the battery for 4 hours and 2 minutes of screen operation (Screen Active Time).

For comparison, the other day when running iOS 26.2, the same device drained 55% of its battery in just 2 hours and 12 minutes of operation. Although it will take more time for the system to fully stabilize, early numbers show that iOS 26.3 Beta 1 is managing power much more effectively than its predecessor.

Micro modem (Modem Firmware) has also been changed to version 1.20.03, promising to improve wave connectivity, thereby indirectly helping to save more battery when using 5G/4G.

Should I update iOS 26.3 Beta 1 now?

Despite its impressive performance and battery life, our sincere advice right now is that you should not rush to install iOS 26.3 Beta 1 on your main device. The reason is that we are entering the Christmas and New Year holidays.

Apple’s engineering team will often be on leave during this period, meaning no Beta 2 updates or bug fixes will be released until mid-January 2026.

If this Beta 1 version develops some serious error during use (for example, a banking application error or software conflict), you will have to live with it for several weeks.

So, continue to enjoy the stability of the official iOS 26.2 and look forward to more in-depth reviews of iOS 26.3 when the holiday season is over.